AN ANALYSIS OF MODULATION EXPERIMENTS FOR RAMAN OPTICAL-ACTIVITY

The dependence of Raman optical activity and the associated artifacts on the scattering angle is discussed in terms of the Stokes-Mueller calculus for the modulation between right and left circular polarization states in the incident laser radiation, in the Raman scattered light, and in both simultaneously. The incident beam modulation technique implemented in backward scattering is identified as the ultimate experimental strategy for measurements on chiral molecules randomly oriented in an optically isotropic phase. Both the incident and the scattered beam modulation techniques have been found to isolate the pure magnetic dipole contribution to the circular intensity differences in right-angle scattering for orientations of the analyzer in the scattered beam and of the azimuth of the linearly polarized incident radiation, respectively, at approx. ±35.26° from the vertical.